The goal of this project is to write a new software package to process data for Protein Crystallography collected with the fine slice method. In this method, each frame of x-ray diffraction is collected with the crystal rotated by a very small angle, for example 0.10 (or smaller). This is to contrast with the standard rotation method where the crystal would rotate by a larger angle in the range of 10 per frame. The fine slice method would yield a better quality data since it would have the smallest amount of background falling on top of each reflection. However, the software will be much more complex since each reflection intensity will be spread out in many flames (it would only be spread out to 1 or 2 flames in a Standard rotation method). We were very successful in the Phase I period. First, we were able to develop a preliminary, but complete software package for the Fine Slice Method. This software contains many new ideas and yields good data with low R[sym] value. In addition, we have discovered a new method that would solve the indexing problem in an automatic way. During Phase II, we would like to extensively test and refine the new software package using at least four outside groups as contacts and, later on, as beta sites. At the end of the Phase II period and after being thoroughly tested, the new software package will be distributed at a low nominal charge. This new software will enhance the protein crystallography data quality which will result in better three dimensional structure of proteins. These structures are now so important because they are used not only to further understand Molecular Biology but also to rationally design new drugs. New HIV protease inhibitors which now can control AIDs disease in most patients are the testimonies of the success of this drug design method. PROPOSED COMMERCIAL APPLICATIONS: Small market but product really needed by protein crystallography community. It could greatly help in drug design procedure.